Yesterday, in American Petroleum Institute v. EPA, the D.C. Circuit Court of Appeals affirmed EPA’s revisions to the National Ambient Air Quality Standard for NOx. The revisions adopted, for the first time, an hourly NAAQS for NOx, in addition to the annual standard.

API made a number of assertions that EPA had been arbitrary and capricious in its review of the scientific evidence concerning potential short-term impacts. The most important were EPA’s reliance, in part, on a study which had not been the subject of peer review, and EPA's alleged failure to consider a study suggesting that short-term impacts had not been demonstrated.

The Court rejected both complaints. With respect to the first, API asserted that EPA violated its own requirements when it relied on an internal analysis that had not been peer-reviewed. The Court’s response was short, but certainly not sweet:

Perhaps the API should have had its brief peer-reviewed. In quoting the EPA’s Review Plan, the API omits the first and most relevant word of the following sentence: “Generally, only information that has undergone scientific peer review … will be considered.” Of course, “generally” here indicates the practice in question will not invariably be followed. A bad start for the petitioners.

To which I can only say, ouch. Significantly, the Court noted that EPAdid have its internal analysis reviewed by the Clean Air Scientific Advisory Committee, and it stated that review by CASAC qualifies as peer review.

Regarding the second claim, the Court concluded that EPA had considered the skeptical study. Moreover, EPA gave reasons why it rejected the conclusions of the study. This was enough for the Court.

I have previously pointed out that the Court’s review of EPA’s NAAQS in recent years has pretty much made the CASAC the final arbiter of the validity of EPA NAAQS promulgations. If EPA’s decision is supported by CASAC’s review – as it was here – EPA’s NAAQS will be affirmed. If, on the other hand, as was the case with EPA’s PM2.5 NAAQS, EPA promulgates an NAAQS that ignores CASAC advice, EPA’s standard is not likely to survive judicial review.

Yesterday’s decision only confirms this analysis. CASAC did not merely review the one paper that API had challenged; it proposed a short-term standard that was similar to and certainly consistent with the standard that EPA ultimately adopted. I’m not sure that Congress meant to delegate to CASAC the determination whether NAAQS adopted by EPA are arbitrary and capricious, but I think that that is where we are today.

American College of Environmental Lawyers, The ACOEL, is a professionalassociation of lawyers distinguished by experience and high standards in the practice of environmental law, ethics, and the development of environmental law.